1. Field of the Invention
The present invention is related with an optical disk of recordable type, and more particularly, an optical disk of recordable type to which information can be recorded by use of a light beam.
2. Description of the Related Art
An optical disk player, for example, a laser disk (LD) player, reads information recorded on a LD by irradiating a light beam to the LD and receiving the reflected light which is modulated by the pit array of the LD.
The light beam is made to follow the pit array in case of optically reading the pit array on the disk in the above-mentioned LD player, so that a tracking control is performed.
In this tracking control, a tracking error signal is generated on the basis of the reflected light from the disk. The light beam is made to follow the pit array at a zero-crossing point when the polarity of the tracking error signal changes from plus (+) to minus (-).
In an ordinary LD to which the information is recorded beforehand, the intensity of the reflected light is low at the pit array of the disk, while the intensity of the reflected light is high between the pit arrays of the disk. Accordingly, it becomes possible to make the light beam follow the pit array at the zero-crossing point when the tracking error signal changes from plus (+) to minus (-), as mentioned above.
Namely, the ordinary LD, the CD (Compact Disk) and the R-CD (Recordable CD), are the recording medium of High-to-Low type in which the intensity of the reflected light is low at the pit array, and with respect to which the tracking control is performed by making the light beam follow the pit array at which the intensity of the reflected light is low.
Apart from that, there is a recordable LD (it is referred as a R-LD, hereinbelow), to which recording is arbitrarily enabled according to a demand of a user. In the R-LD in which the phthalocyanine dye, for example, is used as a recording layer, the intensity of the reflected light is high at the groove portion (i.e. the recording portion) of the disk, while the intensity of the reflected light is low between the groove portions of the disk, on the contrary to the aforementioned ordinary LD. Thus, the light beam cannot be made to follow the groove portion at the same zero-crossing point when the tracking error signal changes from plus (+) to minus (-) as in the case of the aforementioned ordinary LD.
Namely, the R-LD is the recording medium of Low-to-High type, in which the intensity of the reflected light is high at the groove portion. In this case, if the tracking servo were closed at the portion where the intensity of the reflected light is low, in the same manner as the ordinary LD, the light beam would follow the land portion between the groove portions, so that the tracking control on the groove cannot be performed,
In this manner, the tracking polarity at the time of tracking control of this R-LD type is reverse to that of the ordinary LD. Consequently, there is a problem that the R-LD cannot be reproduced by a player for the ordinary LD.
Instead, the R-LD requires an exclusive player to deal with the reverse tracking polarity.